1. Field of the Invention
The present invention relates to lifting devices as used in trucks. More particularly, the present invention relates to apparatus whereby heavy loads can be moved from a location outside of the bed of a truck into the interior of the truck bed and, in particular, in a desired location within the bed of the truck.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
For many years, the advantages of providing a cargo-carrying vehicle such as a truck with a lift gate have been recognized. As is well known, lift gates are gates which not only close the rear of the bed of the vehicle, but which, when in the housing position, may be moved between a first position wherein they are an extension of the truck bed and a second position resting on the underlying terrain. Cargo may be loaded on or removed from the gate while in the latter position or loaded into or unloaded from the vehicle when in the former position. Conventionally, some sort of motor is utilized to drive the lift gate between the two positions. There is some sort of linkage which maintains the upper surface of the gate in a generally horizontal plane during such movement to prevent cargo on the gate from falling off.
Lift gates are generally not suited for small or medium sized cargo-carrying vehicles because the linkage and the drive system for moving the gate between upper and lowered positions was adapted to be located wholly below the plane of the truck bed. This, in turn, requires that the bed of the truck be located relatively high above the underlying terrain to provide the requisite ground clearance. As a result, this is limited to relatively large cargo-carrying vehicles with high road clearances.
Another problem with lift gates is that the cargo is only brought to the very end of the bed of the truck. As a result, it is still necessary to move the heavy load from the lift gate into the bed of the truck. Such movement of heavy loads can be inconvenient and difficult to accomplish. In other circumstances, the heavy load must be lifted a small distance so as to bring the load into proximity onto the lift gate. Once again, workers must be prepared to lift the load, at least a small distance, so as to place the load in its desired position on the lift gate. In many circumstances, the heavy load is only delivered to the very back of the bed of the truck. As a result, the truck will have an unbalanced load heavily oriented toward the rear of the truck. Such unbalanced loads can create driving hazards. Additionally, and furthermore, the lift gates only allow the load to be delivered toward the rear of the bed of the truck. When additional heavy loads must be introduced into the bed, there is often a lack of space for such loads since the initial loads have not been moved toward the forward end of the bed.
In other circumstances, cranes have been proposed for use on such truck beds. Unfortunately, these cranes are often unwieldy devices which prevent the load from being adequately delivered into the interior of the vehicle. In certain circumstances, the cranes will present a structure which extends outwardly above the top of the truck body. As a result, damage can often occur during the movement of the truck with these outwardly extending projections. Additionally, and furthermore, these cranes also fail to deliver the load where it is best desired, i.e. toward the forward end of the bed. These rear-mounted cranes often lift the load to a position whereby the worker can push the load into the rear portion of the pickup truck bed. Once again, limited loads and unevenly distributed loads will result.
In the past, various patents have issued in the past for the loading of the bed of trucks. U.S. Pat. No. 3,637,097, issued on Jan. 25, 1972 to R. R. Horowitz, describes a power-operated tailgate. This power-operated tailgate mechanism has pairs of bell-crank lever arms pivotally mounted on the bed surface and outer ends pivotally connected to a support arm which is attached to the tailgate. The relationship of the pivotal connections is such as to provide a parallelogram linkage for the purpose of maintaining the tailgate surface in a load-carrying attitude during the elevating and lowering movement of the tailgate.
U.S. Pat. No. 3,700,123, issued on Oct. 24, 1972 to Q. D. Corley, Jr., describes a lift frame for attachment to the truck bed. This lift frame includes a tubular horizontal base having integral transverse brackets for attachment to the truck frame and having upright end posts securely welded to the tubular member. A hinged lift platform is provided which is swingably supported by parallelogram arms on the frame end posts. A torque bar connects the lift arms. A hydraulic power cylinder connects one lift arm and one corner post to swing the lift platform between the upper position in the plane of the truck bed and a lower ground position.
U.S. Pat. No. 4,265,585, issued on May 5, 1981 to W. H. Hawkins, teaches a loading device for vehicle beds wherein transversely aligned boom members have an extensible inverted U-shaped member adjustably carried on free ends thereof. The U-shaped member is pivotally secured on a supporting frame and operated by fluid-operated cylinder assemblies which are pivotally connected on one end to a respective boom and on the other end to an upright frame member carried forwardly in the vehicle. The cylinder assemblies ascend above the top of the bed of the pickup truck so that the U-shaped member will rest in a stowed position above the truck bed.
U.S. Pat. No. 5,119,961, issued on Jun. 9, 1992 to L. E. Runn, describes a removable, truck-mounted crane with both an inclined boom for high lift and a horizontal telescoping boom for extended reach beyond the truck. The crane has two winches which can be routed to either boom. A rolling storage stand with winches is used to support the truck tailgate while enabling one person to install or remove the crane from the truck.
U.S. Pat. No. 5,641,262, issued on Jun. 24, 1997 to Dunlop et al., describes a hydraulic lift apparatus whereby the tailgate of the pickup truck can be moved from a lowered position to an upper position.
U.S. Pat. No. 6,019,567, issued on Feb. 1, 2000 to Lutkas et al., describes a slidable load lifting system which can be retracted into the pickup truck. This load lifting apparatus includes a base frame member attached to the truck bed. This base frame member supports a substantially planar roller platform member slidably therein. A pair of elongate rail members extends in parallel and is adapted to engage a set of roller wheels provided on the bottom of the roller platform member. A substantially planar lift platform member is operatively connected to the other roller platform member through a set of parallelogram linkages which allow the lift platform to be moved between a raised position coplanar with the roller platform and a lowered position out of the plane of the roller member for convenient loading of the lift platform at ground level.
U.S. Pat. No. 6,234,741, issued on May 22, 2001 to S. P. McDaniel, describes a forklift for pickup truck. This forklift device is adapted to be installed within the bed of a conventional pickup truck. The horizontal movement of the fork is provided by movement of the truck. When the device is not in use, it is disposed above the forward portion of the truck bed.
Referring to FIG. 1, there is shown prior art the lifting apparatus 10. The lifting apparatus 10 includes a truck 12, a lifting bar 14 and a cylinder assembly 16. Cylinder assembly 16 is connected to the lifting bar 14 through linkage 18. The truck 12 has a bed 20 with a first side wall 22 and a second side wall 24. The bed 20 also has an end opening 26 with a tailgate 28 pivotally attached thereto. The tailgate 28 is pivotable so as to open and close the end opening 26. In one position, the tailgate 28 will be in planar relationship with the bed 20. In the closed position, the tailgate 28 will be upright so as to be transverse to the bed 20. The truck 12 also has a forward wall 30 at an end of the bed 20 opposite the end opening 26. The truck 12, as in the nature of pickup trucks, has a passenger compartment 32 forward of the wall 30.
As can be seen in FIG. 1, the lifting arm 14 has a first side 34 and a second side 36 in parallel relationship to the first side. A crossbar 38 extends between the ends of the sides. The lifting arm 14 has a generally inverted U-shaped configuration. The ends of the sides 34 and 36 opposite the crossbar 38 are pivotally connected at 40 to the side walls of the truck 12. Suitable structures can be employed so as to allow the pivotal movement at 40 to occur without damage to the side walls 22 and 24. A lifting line 42 is affixed to the crossbar 38 generally between the sides. The lifting line 42 is connected to a load 48 such that the load 48 can move upwardly and inwardly relative to the 180 degree range of motion of the lifting arm 14.
With reference to FIG. 1, when it is desired to place the lifting bar 14 in a position for lifting the load 48, a controller (in the passenger compartment 32 or on a side wall of the bed 20) can be actuated so that the cylinder assembly 16 will cause the lifting bar 14 to be moved outwardly of the end opening 26 of the bed 20. When the crossbar 38 is approximately above the load 48, the lifting line 42 can be connected to the load 48. The cylinder assembly 16 can be actuated so that the lifting bar 14 is pivoted about pivot point 40 so as to move the load 48 from the position shown in FIG. 1 to a position within the bed 20. When the crossbar 38 is in a proper position above the bed 20, the lifting line 42 can be released so that the load 48 is in its desired position in the bed 20.
Strong support lines 42 can extend downwardly from the crossbar 38. The pivotal movement of the lifting arm 14 will allow the load 48 to be moved to a desired position within the bed 20. The load 48 can then be released from the lines so as to be placed in a desired position within the bed 20. This allows the load 48 to be placed in any desired location within the bed 20. As such, if multiple loads 48 must be placed within the bed 20, they can be first moved toward the forward wall 30 and then placed in position sequentially thereafter toward the end opening 26. After the load has been placed within the bed 20, the tailgate 26 can be raised upright so that the truck 12 can move to a desired location.
So as to overcome the problems associated with the prior art, the present inventor developed a technology associated with U.S. Pat. No. 6,799,935, issued on Oct. 5, 2004. This patent is illustrated in FIG. 1 herein.
One of the problems associated with the lifting apparatus U.S. Pat. No. 6,799,935 is that there is insufficient clearance between the tailgate 28 of the bed 26 of the truck 12. Ultimately, the fully extended position of the crossbar 38 will be the centerline of objects that are desired to be picked up and placed within the bed of the truck. Under certain circumstances, the load that is to be lifted would not have sufficient clearance so as to be lifted over the tailgate 28 or over the edge of the bed 26 of the truck 12.
There have been significant developments related to remote controlled vehicles for use in military applications. In certain of these applications, military personnel or equipment are delivered by the remote controlled vehicle to a desired location in the field. As such, a suitably large container is placed onto the bed of the truck for delivery. After the container is delivered, the remote-controlled vehicle can be returned to the location of the load for pick up and retrieval. As such, where such large containers are used on such remote controlled vehicles, it is important to provide a lifting mechanism whereby the large container is effectively lifted and returned to the bed of the vehicle.
It is an object of the present invention to provide a lifting apparatus for use in a truck which allows loads to be delivered into the bed of the truck.
It is another object of the present invention to provide a lifting apparatus which allows heavy loads to be placed in any desired position within the bed of the truck.
It is another object of the present invention to provide a lifting apparatus which avoids the use of power-operated tailgates.
It is another object of the present invention to provide a lifting apparatus which can be stowed entirely within the interior of the bed of the truck.
It is still a further object of the present invention to provide a lifting apparatus which entirely avoids the need for human lifting activity.
It is still another object of the present invention to provide a lifting apparatus which provides an entire 180 degree range of motion of the lifting arm relative to its pivot point within the bed of the truck.
It is still another object of the present invention to provide a lifting apparatus which is easy to use, relatively inexpensive, easy to install and simple to manufacture.
It is still a further objected of the present invention to provide a lifting apparatus that allows for relatively large loads to be effectively lifted and to clear the edge of the truck bed or the edge of the tailgate.
It is still a further object of the present invention to provide a lifting apparatus that allows for maximum distance to be achieved between a centerline of the load and the back edge of the vehicle.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.